// HTMLParser Library - A java-based parser for HTML
// http://htmlparser.org
// Copyright (C) 2006 Somik Raha
//
// Revision Control Information
//
// $URL: https://svn.sourceforge.net/svnroot/htmlparser/trunk/parser/src/main/java/org/htmlparser/visitors/TextExtractingVisitor.java $
// $Author: derrickoswald $
// $Date: 2006-09-16 10:44:17 -0400 (Sat, 16 Sep 2006) $
// $Revision: 4 $
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the Common Public License; either
// version 1.0 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// Common Public License for more details.
//
// You should have received a copy of the Common Public License
// along with this library; if not, the license is available from
// the Open Source Initiative (OSI) website:
//   http://opensource.org/licenses/cpl1.0.php

package org.htmlparser.visitors;

import org.htmlparser.Text;
import org.htmlparser.Tag;
import org.htmlparser.util.Translate;

/**
 * Extracts text from a web page. Usage: <code>
 * Parser parser = new Parser(...);
 * TextExtractingVisitor visitor = new TextExtractingVisitor();
 * parser.visitAllNodesWith(visitor);
 * String textInPage = visitor.getExtractedText();
 * </code>
 */
public class TextExtractingVisitor extends NodeVisitor {
	private StringBuffer textAccumulator;
	private boolean preTagBeingProcessed;

	public TextExtractingVisitor() {
		textAccumulator = new StringBuffer();
		preTagBeingProcessed = false;
	}

	public String getExtractedText() {
		return textAccumulator.toString();
	}

	public void visitStringNode(Text stringNode) {
		String text = stringNode.getText();
		if (!preTagBeingProcessed) {
			text = Translate.decode(text);
			text = replaceNonBreakingSpaceWithOrdinarySpace(text);
		}
		textAccumulator.append(text);
	}

	private String replaceNonBreakingSpaceWithOrdinarySpace(String text) {
		return text.replace('\u00a0', ' ');
	}

	public void visitTag(Tag tag) {
		if (isPreTag(tag))
			preTagBeingProcessed = true;
	}

	public void visitEndTag(Tag tag) {
		if (isPreTag(tag))
			preTagBeingProcessed = false;
	}

	private boolean isPreTag(Tag tag) {
		return tag.getTagName().equals("PRE");
	}

}
